/*
 * Copyright 2020 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cc.siyecao.mapper.provider.entity;

import cc.siyecao.mapper.provider.defaults.GenericTypeResolver;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * 实体类信息接口，继承当前接口即可在接口中方便的获取当前接口对应的实体类类型 {@link Class}和实体表的信息 {@link EntityTable}
 *
 * @param <T> 实体类泛型
 * @author liuzh
 */
public interface EntityInfoMapper<T> {

    /**
     * 获取当前接口对应的实体类类型
     *
     * @return 当前接口对应的实体类类型
     */
    default Class<T> entityClass() {
        return (Class<T>) CachingEntityClass.getEntityClass( getClass() );
    }

    /**
     * 获取当前接口对应的实体表信息
     *
     * @return 当前接口对应的实体表信息
     */
    default EntityTable entityTable() {
        return EntityFactory.create( entityClass() );
    }

    /**
     * 缓存实体类类型
     */
    class CachingEntityClass {
        static Map<Class<?>, Class<?>> entityClassMap = new ConcurrentHashMap<>();

        /**
         * 获取接口对应的实体类类型
         *
         * @param clazz 继承的子接口
         * @return 实体类类型
         */
        private static Class<?> getEntityClass(Class<?> clazz) {
            if (!entityClassMap.containsKey( clazz )) {
                entityClassMap.put( clazz, (Class<?>) GenericTypeResolver.resolveType(
                        EntityInfoMapper.class.getTypeParameters()[0], clazz, EntityInfoMapper.class ) );
            }
            return entityClassMap.get( clazz );
        }
    }

}
